Wire wrapped well screen

ABSTRACT

A well screen in which wire having accurately formed spacing lugs therein is helically wrapped around a tubular pipe having concave arcuate grooves longitudinally formed in the outer surface thereof and either through slots or perforations intersecting the grooves at the point of deepest penetration thereof to produce a funnel effect. In addition to the more conventional keystone wire, there is further disclosed two subspecies of wire having a cross-section including a concave arcuate, preferably semicircular, segment to increase the transverse flow area between windings and enhance the circumferential flow.

United States Patent 1 Layne, II et al. 7

[11] 3,709,293 r Ja'n.9,1973

[54] WIRE WRAPPED WELL SCREEN [75] Inventors: Leslie A. Layne, 11, Houston, Tex.;

Fred W. Gerwick, Lafayette, La.

[73] Assignee: The Layne & Bowler Company,

Houston, Tex.

[22] Filed: Feb. 22, 1971 [21] Appl. No.: 117,555

[52] US. Cl ..166/232, 166/233 [51] Int. Cl. ..E2lb 43/08 [58] Field of Search ..166/227, 231, 232, 233; 210/497.1

[56] Referenees Cited 1 UNITED STATES PATENTS 1,273,236v 7/1918 Layne ..166/233 1,202,515 10/1916 Hardin et al ..166/233 2,120,983 6/1938 Layne ..l66/232 X 3,385,373 5/1968 Brownm, r ..166/232 975,334 11/1910 Decker et 31.... ..166/233 1,845,265 2/1932 Getty ..l66/232 1,878,432 9/1932 Whann .166/23 2 2,744,579 5/1956 Gerhardt .166/233 X 3,221,819 12/1965 Dickinson et al ..166/233 Primary Examin erDavid H. Brown Attorney-Arnold, White & Durkee, Tom Arnold, Bill Durkee, Jack C. Goldstein, John F. Lynch, Louis T. Pirkey, Frank S. Vaden, III and Robert A. White [57] ABSTRACT A well screen in which wire having accurately formed spacing lugs therein is helically wrapped around a tubular pipe having concave arcuate grooves longitudinally formed in the outer surface thereof and either through slots or perforations intersecting the grooves at the point of deepest penetration thereof to produce a funnel efiect. in addition to the more conventional keystone wire, there is further disclosed two sub-species of wire having a cross-section including a concave arcuate, preferably semicircular, segment to increase the transverse flow area between windings and enhance the circumferential flow.

6 Claims, 6 Drawing Figures PATENTEDJAN 9191a 3.709293 Fred W Gerwick INVENTORS wuwme x Uwufiee ATTORNEYS Leslie A. Layne; H I I BACKGROUND OF THE INVENTION This invention relates generally to well screens and more particularly to Wire wrapped well screens.

As shown by US. Pat. Nos. 1,273,236, issued to Layne on July 23, 1918, 1,845,265, issued to Getty on Feb. 16, I932, and 2,046,459, issued to Johnson on July 7, 1936, as well as Composite Catalog of Oil Field Equipment and Services, 17th rev. ed,, Houston, World Oil, Gulf Publishing Company, I950, pp. 1832-1833, the prior art has long recognized the capabilities of well screens of the type wherein a wire, having accurately formed s'pacing lugs disposed therealong, is helically wrapped around and secured to .a longitudinally grooved pipe after it has been radially drilled or slotted.

As discussed in the aforementioned Getty patent, the longitudinal grooves obviously tend to weaken the walls of the supporting pipe. Accordingly, to optimize the strength of the pipe, the prior art has contemplated that the bottoms of the grooves should be a convex arc, concentric with the surfaces of the pipe. However, due to the high cost of fabrication of that type of groove, the prior art has generally employed grooves with flat bottoms.

Applicants have observed the inherent disadvantage of grooves with either convex, arcuate, or flat bottoms is that the production fluid is in no way funnelled toward the drilled perforation or slot which provides the fluid communication between the grooves and the interior of the pipe.

SUMMARY OF THE INVENTION the interior of the pipe and the grooves, preferably at.

an area' including the point of deepest penetration of the respective groove into the pipe.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the invention and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is an elevation view, partly in section, of a portion of a well screen embodying the present invention;

FIG. 2 is aplan view of a well screen embodying the present invention; I I

FIG. 3 is a sectional plan detail view of a portion of a supporting pipe for use in well screens embodying the present invention;

FIG. 4 is a cross-sectional view of one species of wire suitable for use in well screens embodyingthe present invention; and

FIGS. 5 and 6 are cross-sectional views of two subspecies of another species 'of wire suitable for use in well screens embodying the present invention.

FIG. 2, are formed through pipe 12 providing fluid' wire is wrapped therearound.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings wherein like reference characters designate identical or corresponding parts throughout the several views, and more particularly to FIG. 1 thereof wherein there is shown a section of a well screen 10, embodying the present invention, com- I prising a tubular supporting pipe 12 and a wire 14 helicallywrapped around the outside thereof.

As shown more clearly in FIG. 2, a plurality of elongate, preferably longitudinally extending, grooves 16, circumferentially spaced from one another and having concave, arcuate,transverse cross sections 18 as shown in detail in'FlG. 3, are formed at the outer surface of pipe 12. According to the preferred embodiment, there are thirteen grooves 16 equally circumferentially spaced from one another; however, it should be apparent that the exact number of grooves and spacing thereof are not limitations of the present invention.

Radially extending apertures, such as elongate slots 20 shown in FIG. I or circular perforations 22 shown in communication between grooves 16 and the interior of the pipe. Preferably, of course, each aperature intersects a groove at an area including the point of deepest penetration of that groove into the pipe to optimize the funnel action provided by the concave, arcuate cross section of the grooves. As shown in FIG. 1, adjacent apertures preferably are longitudinally staggered; but that is well known in the art and is not an essential feature of the present invention.

Adjacent windings of wire 14 may be spaced from one another by lugs 24 accurately formedintegrally therein at spaced intervals therealong as is also well known in the art. The wire is heldin place by one or more longitudinal weld beads (not shown) which preferably do not extend completely through the Wire.

Although screens embodying the present invention may-employ conventional wire known in the art as keystone wire and shown'in FIG. 4, other wires, such as those shown in FIGS. 5 and 6, may also be used.

. As shown in'FlG. 4, a keystone Wire 26 has a cross section in the shape of an isosceles trapezoid. There are two parallel, generally linear segments 28 and 30, the latter being the shorter of the two, and two equal lengths, generally linear segments 32. In use, short segment 30 abuts the outer surface of There is shown in FIG. 5 a'wire 34 having a more unusual cross section designed to provide a greater transverse flow area for circumferential flow between windings. The cross section of wire 34 includes two parallel, general linear segments 36 and 38, the latter being the shorter of the two. Another generally linear segment 40 insersects sides 36 and '38 at an acute angle with the former and at an obtuse angle with the latter;

therearound. It should be apparent that there will be a greater open space .between adjacent windings withv wire 34 than with wire 26 andthat the circumferential flow would thereby be enhanced.

pipe 12 when the Wire 34 shown in'FlG. 6 is similar to wire 34 shown in FIG. the principal difference being linear segment 44 intersecting segments 36 and 40 in wire 34'.

As may be seen most clearly in FIG. 2, the use of a groove having a concave arcuate cross section intersected by an aperture at the point of deepest penetration of the groove into the pipe tends to funnel the fluid in the groove'toward the aperture to enhance the flow of fluid in the groove into the interior of the pipe. It has been found that the loss in strength, if any, due to the use of a concave arcuate groove as compared with a convex arcuate groove or a flat bottomed groove is generally insignificant in terms of the screens capability for field use. Accordingly, the enhanced flow is attained in a screen having satisfactory strength in contradiction to the teachings of the prior art.

Obviously, numerous modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. i g

What is claimed as new and'desiredto be secured by Letters Patent of the United States is: g

1. A well screen, comprising: I a tubular pipe having I Q a plurality of elongate longitudinal grooves formed therein at the outer surface thereof and a plurality of apertures extending radially through said pipe and intersecting the grooves; a wire helically disposed around the outside of said pipe,. said wire having comprising a first substantially linear segment,

a general cross-sectional shape and the other end disposed'proximate one end of said second segment, said third segment being disposed obtusely relative to said first segment and acutely relative to said second segment, and

a fourth concavely disposed curved segment having one end disposed proximate the other end of 7 said first segment and the other end disposed proximate the other end of said second segment; and

means to space adjacent windings of said wire from one another.

2. The screen of claim 1 wherein said third segment intersects said first segment at said one end thereof and said second segment at said one end thereof.

3. The screen of claim 1 wherein the cross-sectional shape of said wire further comprises a fifth substantially linear segment disposed substantially perpendicular to said first and second segments and having one end disposed proximate said one end of said secondsegment and the other end disposed proximate said other end of said third segment. v

4. The screen of claim 1 whereinsaid grooves have concave, arcuate transverse cross sections and wherein the intersections of the apertures with the grooves in clude the point of deepest penetration of the respective groove into said p tpe.

5. The screen 0 claim 4 wherein the apertures comprise elongate slots disposed longitudinally relative to' said pipe.

6. The screen of claim 4 wherein the apertures comprise circular perforations. 

1. A well screen comprising: a tubular pipe having a plurality of elongate longitudinal grooves formed therein at the outer surface thereof and a plurality of apertures extending radially through said pipe and intersecting the grooves; a wire helically disposed around the outside of said pipe, said wire having a general cross-sectional shape comprising a first substantially linear segment, a second substantially linear segment longer than and disposed parallel to said first segment, a third substantially linear segment having one end disposed proximate one end of said first segment and the other end disposed proximate one end of said second segment, said third segment being disposed obtusely relative to said first segment and acutely relative to said second segment, and a fourth concavely disposed curved segment having one end disposed proximate the other end of said first segment and the other end disposed proximate the other end of said second segment; and means to space adjacent windings of said wire from one another.
 2. The screen of claim 1 wherein said third segment intersects said first segment at said one end thereof and said second segment at said one end thereof.
 3. The screen of claim 1 wherein the cross-sectional shape of said wire further comprises a fifth substantially linear segment disposed substantially perpendicular to said first and second segments and having one end disposed proximate said one end of said second segment and the other end disposed proximate said other end of said third segment.
 4. The screen of claim 1 wherein said grooves have concave, arcuate transverse cross sections and wherein the intersections of the apertures with the grooves include the point of deepest penetration of the respective groove into said pipe.
 5. The screen of claim 4 wherein the apertures comprise elongate slots disposed longitudinally relative to said pipe.
 6. The screen of claim 4 wherein the apertures comprise circular perforations. 